Tagged Questions

Stars are astronomical bodies that are (usually) mainly composed of Hydrogen, Helium, and Lithium. They are massive enough that their gravity compresses the matter to the point where nuclear fusion occurs, which creates a lot of heat and tends to make stars output radiation along a blackbody curve. ...

Astronomy is far older than nuclear physics. So there was a long time in which fire was a reasonable explanation for the sun burning.
Has any scientist figured out the sun cannot possibly be a normal ...

That is may be a easy question, but I am not a professional. The sun is a star and when I look at the sun is usually yellow. Why stars in the night are white? I suppose is for the distance. What is ...

Considering our Sun/stars (on the most basic terms) have often been referred to as a hydrogen fusion engines/machines... what type/class of engine/machine have scientists actually assigned to planets, ...

Sunlight can be treated as BB radiation. Why is it a continuous spectrum while the sun contains only a few elements and the radiation from the jumps between atomic levels are discrete? How does the ...

I know that stars are formed from dense regions in large gas clouds.
I know that when gravity causes the mass of the clump to get so big that its internal pressure can't sustain it, it collapses and ...

I am trying to figure out how the first stars formed and I'm looking for information on what made up the gas/radiation that they formed from.
Most of our evidence for the make up of these formations ...

This is a question that has puzzled me for some time. As a star emits light, the light travels away from the star. If you were to pick any spot on the star and draw a line extending outwards and then ...

I read some about red giants and so far I understand red giants become exhausted of burning hydrogen in the core, so then start hydrogen burning at shell and may or may not be burning helium in the ...

Suppose a star is 100 light-years away from the Earth. Therefore, the light coming from the star (which carries its information) takes roughly 100 years to reach Earth. However, if in the meantime the ...

In stellar atmospheres, if we are given the gas pressure on the surface level of a star $P_{0}$ and we are expected to calculate the gas pressure on a deeper level (say 10000km) of the star, what kind ...

The equation of states for a star is given by a polytropic equation, where density depends on the $n$th power of $\theta$. Please refer to the literature
First, what is this $\theta$? It can't be a ...

I am rather a beginner to this field, so please forgive me if this is a very meaningless question. If I were to somehow increase Jupiter's mass by adding more hydrogen to its atmosphere, can I ever ...

According to the virial theorem, when a protostar contracts, half of the gravitational potential energy is radiated and half is kept as kinetic energy of the falling material which in turn heats the ...

Trying to find an estimate for the stellar mass of the MW galaxy, I found this paper and the estimated stellar mass is $~6.5 \times 10^{10} M_{\odot}$.
I was also trying to understand the methods used ...

According to the IMF and the stellar mass distribution, stars become more abundant the less massive they are. And while objects must have a mass > 0.075 solar mass to become a star, brown dwarfs with ...

I have been trying to find an answer for this question for a while without a success, so I guess it might not have a specific answer. But to make things easier, let's take the Milky Way galaxy as an ...

Has the number of new stars being formed decreased at all over the age of the universe? Would this be because the average density of the universe is decreasing due to the expansion of the universe, it ...

We know that we can focus radiation of sun and can burn a paper. If we think of this thought experiment, will that happen? If someone constructs a concave mirror on the sun and concentrate radiation ...

We know from big bang nucleosynthesis that baryonic matter accounts for about 5% of the universe's total mass-energy density. What is the current best estimate of how much of this is in the form of ...

According to this, our Earth's atmosphere is completely opaque to radiation with wavelengths less than 100 nm as this radiation has enough energy to ionize the air.
Since the surface temperature of ...